ABSTRACT
Pexophagy is the selective degradation of peroxisomes by the yeast vacuole. In Pichia pastoris, pexophagy occurs when cells adapt from utilizing methanol as the sole carbon source to metabolizing glucose. Upon glucose adaptation from methanol, the peroxisomes are engulfed within the vacuole by an invagination at the vacuole surface followed by the extension of arm-like projections of the vacuole, which sequester the peroxisomes. Once inside the vacuole the peroxisomes are rapidly degraded by the hydrolytic enzymes present. At least 21 genes have been identified that are known to be essential for glucose-induced pexophagy. A few of these genes appear to be required for the regulation of pexophagy while many of them are essential for the sequestration of peroxisomes and others are necessary for the degradation of peroxisomes. In this chapter, we will discuss our current understanding of the functional roles of these genes in the molecular events of pexophagy.
